package com.thread.exe;

import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.ReentrantLock;

public class AAAA {
	public static void main(String[] args) {
		AtomicReference<Integer> s = null;
		s.compareAndSet(null, 1);
		System.out.println(s);
	}
}
